I took more than 200 CDs and asked myself which ones would maybe have transients the would be close to Amnesia, and cause problems with MPC.I found 41 tracks with more or less transients, but none of them have as strong ones as amnesia, and none of them caused obvious problems to MPC encoding (I didn't search for artifacts smaller than the ones in Amnesia, and I only listened to the parts with transients), which is comforting :

Funny thing is that if the source amnesia.wav is 48kHz, standard sounds clearly better than if the source amnesia.wav is first downsampled to 44.1kHz and then encoded with 1.15r standard.

I can clearly ABA (4/4) the difference between the MPCs depending whether the source has been 48khz or 44.1khz. 44.1khz version sounds clearly worse: noise spreading around and more watery sound. I hear it better if I try to forget the "choir" and don't use too high volume.

I uploaded 44.1kHz here: amnesia44.flac. It's downsampled from the original using CoolEdit2pro quality 999.Here is the original 48khz amnesia.flac.

edit. Well, you can see also from the spectral view, that if the source was 44.1kHz, the resulting MPC's spectra has larger dropouts.

Funny thing is that if the source amnesia.wav is 48kHz, standard sounds clearly better than if the source amnesia.wav is first downsampled to 44.1kHz and then encoded with 1.15r standard.

I can clearly ABA (4/4) the difference between the MPCs depending whether the source has been 48khz or 44.1khz. 44.1khz version sounds clearly worse: noise spreading around and more watery sound. I hear it better if I try to forget the "choir" and don't use too high volume.

I uploaded 44.1kHz here: amnesia44.flac. It's downsampled from the original using CoolEdit2pro quality 999.Here is the original 48khz amnesia.flac.

edit. Well, you can see also from the spectral view, that if the source was 44.1kHz, the resulting MPC's spectra has larger dropouts.

Where can I see the spectral plots? (44.1 + 48)Is the noise a continuous noise or is it only sometimes audible?What say 1.95z6 with 44.1/48/64 kHz?What headphones / loudspeakers do you use (I hope nothing like HD570/HD575/HD590)?RMS level in Volts on loudspeakers?Is there a need of a switch which headphone/loudspeaker do you use for listening?

Below are the graphs for comparing 48khz and 44khz amnesia using mppenc 1.15r standard.

48kHz version 0.43-0.76s sounds closer to the original. (downsampled after encoding to 44khz for easier graphical comparison)44kHz version 0.43-0.76s has 2 increased spreading noise bursts, probably where the big dropouts happen around 0.53s and 0.64s.

I think this is the most audible difference, but there's all the time positions where 44kHz version gives a bit louder noise bursts than 48khz. I'm not saying that 48khz is transparent, but it's better than 44khz.

Anyway, these were definitely very much harder than without lowpass, because most of the revealing spreaded "buzz" burst noise in the 44khz mpc's problem section was gone. But still the "buzz" bursts left were slightly more "monoish" with the original and 48khz version which allowed to distinguishing the 44khz.

Also check other samples like Jump.wav.It doesn't help when - only amnesia is enhanced - bitrate increases for all music pieces, also for those without any problems

I have a decent amount of music similar to amnesia; could you roughly explain what types of sounds you think are causing the problem, helping me limit my search? Is the problem caused by sharp transients (which I thought would be unlikely given MPC's short time resolution) or distortion or parts with a gapper applied to them, or...?

I tried a track with sharp transients and lots of distortion that yanked 200kbps average out of MPC --standard (and 250kbps out of --alt-preset standard), but was unable to ABX any differences between it and the original when using 1.95z6, which I have to say I'm very impressed about.

hi, i don't think to have as much expertise as the ones writing in this topic i am just asking a questions about preparing trouble samples to hear artefacts easily: you can try it with sound editor (wablb, kooledit)normalize the volume of one audio channel to max (100%)the other channel has its volume gain lowered to say 10% or lessencode the file then the artefacts are really easy to find

I found another sample of the same kind. The effect is the same, but less strong. But this time, it is ripped straight from a CD without resampling nor normalisation. And lame APS performs poorly on it.

I hope that Frank can come up with his magic to solve this the best possible way. I know he has been in contact with Andree B, and they have a pretty good idea what the problem is. The difficult thing is, how to implement the solution in best possible way.